Percentage change calculator

How to use the percentage change calculator

1. Type the starting value in the "from" box.
2. Type the new value in the "to" box.
3. Read the percentage change (a minus sign means it fell) and the difference.

The percentage change formula, with examples

Percentage change = (new - old) / old x 100. Always divide by the old, starting number.

• Sales went from £80,000 to £92,000: (92,000 - 80,000) / 80,000 x 100 = 15% increase.
• A train fare went from £45 to £52.20: 7.20 / 45 x 100 = 16% increase.
• Your energy bill fell from £160 to £136: -24 / 160 x 100 = 15% decrease.

Direction changes the answer. £80 to £100 is a 25% increase, but £100 to £80 is a 20% decrease. The £20 difference is the same both times; the starting point is not.

Percent vs percentage points

When the thing you are measuring is itself a percentage, such as an interest rate or a pass rate, there are two ways to describe a change, and they give very different numbers.

If a savings rate goes from 4% to 5%, it has risen by 1 percentage point. As a percentage change it has risen by 25%, because 1 is a quarter of 4. Both statements are true. News reports about interest rates usually use points, while adverts sometimes pick whichever sounds bigger.

Use percentage points for the plain gap between two percentages, and percent for the relative change.

When the starting number is zero or negative

A change from zero has no percentage, because you cannot divide by zero. Going from £0 to £500 of profit is a £500 rise, not an infinite one. Changes to or from negative numbers (a loss turning into a profit) also give odd-looking percentages, so quote the difference in pounds instead.

Questions people ask